ARRL

ARRL Propagation Bulletin ARLP047 (2010)

SB PROP @ ARL $ARLP047
ARLP047 Propagation de K7RA

ZCZC AP47
QST de W1AW  
Propagation Forecast Bulletin 47  ARLP047
From Tad Cook, K7RA
Seattle, WA  November 29, 2010
To all radio amateurs 

SB PROP ARL ARLP047
ARLP047 Propagation de K7RA

Average daily solar flux declined this week over 36 points compared
to last week, to 24.6.  Our reporting week, which ran until November
24, showed the daily sunspot number declining from 40 to 11, but on
November 25 the sunspot number rose to 22.

Sunspot group 1125 disappeared on November 17, and on November 20
sunspot group 1124 was gone, after ten days of visibility.  1126 was
gone on November 23 (after 11 days), and 1127 is still visible after
ten days.  On November 25 new sunspot group 1128 arose near the
eastern horizon, and may provide some needed propagation juice for
this weekend's CQ World Wide CW DX Contest.

Solar flux during this week went from a high of 86.5 to 74.8, and
the predicted solar flux for November 26-30 is 78, 78, 79, 80 and
80. Solar flux is predicted at 78 for December 1-3, then 85 on
December 4-11 and 90 on December 12-14.  Perhaps this bodes well for
the ARRL 10 meter Contest, December 11-12.  That contest is also
during a time when ionization from meteors may enhance 10 meter
propagation.

The above solar flux forecast is from NOAA and USAF, and they say
planetary A index should be stable for the next couple of weeks,
with the index at five for November 26 through December 10.
Geophysical Institute Prague has a different outlook.  They also say
that for the next week, look for quiet conditions November 26,
quiet-to-unsettled November 27, unsettled November 28,
quiet-to-unsettled November 29, and quiet November 30 through
December 2.

This weekend the STEREO mission (see http://stereo.gsfc.nasa.gov/)
will achieve 97.3% coverage.  This means that only 2.7% of the Sun
is now not visible to us, and that is in the area on the side of the
Sun facing away from Earth.  STEREO will achieve 98.7% coverage by
the end of this year, and should finally achieve 100% coverage some
time on February 6, 2011.

Things are still looking up in terms of increasing sunspot activity.
The first 25 days in November had an average daily sunspot number of
38, compared to 18, 23.1, 28.2, 35.7 and 35 for June through
October.  If this average continues through the next five days,
November will have the highest monthly average of daily sunspot
numbers since May, 2006 when it was 39.6.

A brief report from Pete Heins, N6ZE of Thousand Oaks, California
(DM04): On November 19 at 0056 UTC with 100 watts and a vertical he
worked VP8LP in the Falkland Islands, with S5 reports both
directions.  VP8LP was working mostly W6, W7 and VE7.  For details
on Pete's VHF exploits, see http://www.qrz.com/db/n6ze.

Larry Jones, K5ZRK of Sandersville, Mississippi lives on the edge of
the Tallahala Swamp. He wrote, "I operate only 30 and 60 meters.  On
60 meters I have a separate receive antenna. The morning of November
17 while in QSO with Les, KG4QZV (in Rome, Georgia, about 300 miles
away), after Les un-keyed I heard a very distinct echo off his
signal. We were on 5.3465 MHz.  The echo had less signal strength
than Les's originating signal.  I have only heard this happen once
before on 60 meters and I chase the gray line on this band every
day.  Is this long path or diversity reception?  I might also note
that the gray line was very productive this same morning."

Hard to say what was causing that echo, but at 186,000 miles per
second, a 30 ms echo could emerge if the signal traveled 2700 miles,
bounced, and covered the same distance back.  Seems unlikely to be
long path, but perhaps that gray line was propagating that signal a
long distance, and propagating the echo back.

Read more about Larry's QRP activity on 30 and 60 meters at
http://www.qrz.com/db/k5zrk.

Some readers who read this bulletin in the html version on the ARRL
web site had trouble linking to the PDF provided by Dean Straw, N6BV
last week.  Try the text version at
http://www.arrl.org/w1aw-bulletins-archive/ARLP046/2010 and
right-click and save via the link provided for the PDF of "Seeing
the HF Propagation Big Picture."

Carl Luetzelschwab, K9LA has a piece on HF circular polarization in
his Propagation column in the current issue of World Radio at
http://www.worldradiomagazine.com.

Thanks to K1SFA for posting this bulletin to the ARRL web site from
her home on Friday, November 26.  The email version won't propagate
until Monday, November 29.

If you would like to make a comment or have a tip for our readers,
email the author at, k7ra@arrl.net.

For more information concerning radio propagation, see the ARRL
Technical Information Service web page at
http://arrl.org/propagation-of-rf-signals. For an explanation of the
numbers used in this bulletin, see
http://arrl.org/the-sun-the-earth-the-ionosphere. An archive of past
propagation bulletins is at
http://arrl.org/w1aw-bulletins-archive-propagation.  Find more good
information and tutorials on propagation at
http://mysite.ncnetwork.net/k9la/index.html.

Monthly propagation charts between four USA regions and twelve
overseas locations are at http://arrl.org/propagation.

Instructions for starting or ending email distribution of ARRL
bulletins are at http://arrl.org/bulletins.

Sunspot numbers for November 18 through 24 were 40, 37, 24, 25, 23,
12, and 11, with a mean of 24.6. 10.7 cm flux was 86.5, 84, 79.8,
77.6, 74.8, 75.3 and 75.8 with a mean of 79.1. Estimated planetary A
indices were 5, 2, 2, 3, 4, 8 and 4 with a mean of 4. Estimated
mid-latitude A indices were 4, 2, 2, 2, 4, 7 and 3 with a mean of
3.4.
NNNN
/EX